Bullet decelerator



p 1958 R. E. BOWLES 2,853,008

BULLET DECELEIRATOR Filed April 23, 1958 fig. 5.

I l- INVENTOR Roma/d E Bow/ es BY m2 Maw-$1M? ATTO EYS.

United States Patent 2,853,008 BULLET DECELERATOR Romald E. Bowles,Silver Spring, Md., assignor to the United States of America asrepresented by the Secretary of the Army Application April 23, 1958,Serial No. 731,579

1 Claim. (Cl. 10265.2)

(Granted under Title 35, U. S. Code (1952), sec. 266) The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment to me of any royaltythereon.

This application is a continuation-in-part of application Serial No.584,155, filed May 10, 1956, now abandoned.

This invention relates to an improved bullet decelerator and stopperwhich can be inserted into the tube of a rifle grenade so as to permitthe launching of the rifle grenade with a regular ball, incendiary, orsteel-jacketed ammunition, rather than special blank cartridges.

At present, rifle grenades are launched by attaching a launcher to aconventional rifle, placing a grenade with a tube snugly on thelauncher, loading the rifle with a special grenade (blank) cartridge andfiring the cartridge. It is especially desirable that a grenade be ableto be launched without resorting to use of such special blankcartridges. This is firstly because the blank cartridge is a specialitem which mustbe supplied to the troops. Secondly, disastrous resultsoccur if regular steeljacketed ammunition is used with grenades designedto be fired by this special blank ammunition.

The prior art has tried to solve this difiicult problem of adaptingrifle grenades so that they can be launched by regular steel-jacketedammunition. One solution has been to embody bullet decelerators in thegrenade tube. This has been done by tapering the bore in the riflegrenade tube and using flat discs to decelerate the bullet. The forcesproduced by the bullet punching through the discs transmit enoughvelocity to drive the grenade. These discs present fiat verticalsurfaces to the rotational axis of the bullet. This shape andpositioning of the discs are most desirable because jacketed bulletshave very little tendency to deflect from these flat surfaces. Forexample, U. S. Patent No. 1,900,790 discloses a tapered tube which has aseries of spaced flat discs which act as described above.

One of the main drawbacks of the tapered tube and vertical discarrangement illustrated in the above-mentioned patent is that becausethe bullet diameter is larger than that of the tube, the bullet impactswith the walls of the grenade tube during its passage therethrough'Since the bullet is fired at high velocity, this impact with the wall ofthe tube frequently causes the wall to crack or split lengthwise. Oftenthe split or crack so formed is large enough to permit the bullet topass angularly out through the tube wall causing a change in flightdirection as well as loss of velocity to the grenade.

The improved bullet decelerator and stopper in accordance with thisinvention overcomes the problem of the bullet passing out angularlythrough the tube wall. This is accomplished by utilizing a grenade tubehaving a diameter greater than that of the bullet with an improvedbullet decelerator and stopper. A series of relatively thin flat discsand washers, which are alternately stacked together in the grenade tube,form this improved 2,853,008 Patented Sept. 23, 1958 "ice bulletdecelerator. The discs serve to drive the grenade when they are struckby the bullet and the washers guide the bullet substantially axiallythrough the tube. If the Washers are cracked by grazing impact of thebullet, the crack so formed is not transmitted to the tube and extendsonly for the width of one washer. Thus, there will be no cumulativecracking effect of the tube, which was common in known prior artdecelerators.

A general object of this invention is to provide a bullet deceleratorwhich can be used with present grenades and fuzes.

Another object is to provide a rifle grenade which may be launched byall types of ammunition including metal-jacketed and incendiaryammunition as well as by special grenade ammunition.

More specifically, it is an object of this invention to provide animproved bullet decelerator which orients the bullet in its passagethrough the tube and prevents the bullet from passing angularly throughthe walls of the grenade tube.

Another object is to provide a test device for subjecting objects tohigh acceleration.

Still further objects are to achieve the above with a device that issturdy, simple and reliable, yet cheap and easy to manufacture.

The specific nature of the invention as Well as other objects, uses andadvantages thereof will clearly appear from the following descriptionand from the accompanying drawing, in which:

Fig. 1 is a cross-sectional view of a rifle grenade with a bulletdecelerator in accordance with this invention.

Fig. 2 isa fragmental cross-section of a modified form. of the device ina rifle grenade.

As seen in Fig. l, a conventional rifle grenade comprises the grenadeproper 10 containing an explosive charge 12, a fuze 14 in the well 15which is separated from tube 16 by bulkhead 17, and fins 18 on the tube.It is shown on a conventional launcher 20.

One form of this invention involves lengthening tube 16 and inserting abullet decelerator stack 21 comprising coaxial discs 22 and Washers 24-in it. The stack as shown consists of a washer 24 seated against thebulkhead 17, followed by seven discs 22, followed by six pairs ofwashers and discs, followed by a disc, all snugly retained by ring 26 inseat 28.

I have obtained good results using titanium discs and washers. I havealso successfully used. aluminum and cold-rolled steel, particularlyusing steel discs and aluminum Washers. Although the bullet deceleratorstack adds weight to the grenade, this is compensated for by thetransfer of energy to the grenade from the momentum of the bullet. Thebullet in contained in the stack, coming to rest in the seven forwarddiscs.

This same bullet decelerator stack can be used in test devices. If it isdesired to study the effect of acceleration on an object, the object maybe inserted in the wall 15, or substituted for grenade proper 10 andsubjected to acceleration by firing a bullet into the stack 21.

Fig. 2 shows a modified form of the invention. In it a bulletdecelerator stack 30 is contained in a tube 32 of a rifle grenade (thegrenade proper is not shown in this view) which is adapted to fit withina launcher 34 which would be designed for the system. The tube 32 mustbe sufiiciently thick to prevent the tube 32 from locking to thelauncher 34.

The stack 30 consists of seven washers 24, nine discs 22 and fourwashers 36. The inside diameter of the washers 36 is slightly less thanthat of the bullet to be stopped. The stack is arranged in the followingsequence: one washer 24 at the forward end of the tube,

' three discs 22, four washers 36 and six pairs of washers 24 and discs22 all snugly retained by ring 26 in seat 28. The inclusion of thewashers 36 change the deceleration characteristics of the bullet in thisarea.

Discs 22 and washers 24 are stacked together, in .tube 16, as shown inFigs.;1 and 2,.fand form a compact bul-. let decelerator. The bores ofthe washers 24 and the discs 22 are coaxial with respect to thelongitudinalaxis of tube 16, and the widths-of the washers and discs aresubstantially equal. In a preferred embodiment; the width or thicknessof the washers .and discs is approximately one-fifth the lengthoftheelongated bullet fired into the grenade tube 16. The inner diameter 'orbore of the washer is preferably approximately .one' .and.1a half timesthat of the bullet diameter.

1 'When the bullet is firedinto the tube 16, -it'isTusually deflectedfrom its axial course after it penetrates a disc 22. Since the washers24 and discs 22 are alternately stacked together and since they arerelatively thin with respect to the length of the bullet, the bore of awasher upon-receiving a grazing impact from the deflected bulletwill actto reorient the bullet so that it can strike the next disc substantiallycentrally thereof; This is because the bullet tends to follow a path ofleast resistance. The grenade is thereby driven in the same directionsince the bullet is always guided by the washer bores substantiallyaxially through the tube 16.

An important advantage of the embodiments herein described is that 'eventhough the bullet in its passage through tube 16 will graze the bores ofwashers 24, causing breaks or cracks to occur in the washers, any cracksor breaks so formed will be limited .to the thickness. of the washer andwill not be cumulative.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can-be made in construction, materials, andarrangement within the scope of the invention as defined in the appendedclaim.

I claim as my invention: A-bullet deoelerator for-use propelling; agrenade,

comprising: a cylindrical tube having one end fixed to the grenade, saidtube having a bore extending longitudinally therein, adapted to receivean elongated bullet driven axially into said bore, a closure for saidbore at the grenade end of said tube, a stack of cylindrical discs andwashers alternately arranged within the tube bore, one end of said stackcontacting said closure, said cylindrical discs and washers 'havingouter diameters substantially equal in size, said diameters beingslightly less than the diameter of said tube bore, said discs andwashers being coaxial with said tube bore, each disc and washer havingflat opposite end surfaces which are perpendicular to the longitudinalaxes of said tube bore, said opposite flat surfaces defining thethickness of each disc and washer, the end surfaces of each washercntacting end surfaces of successively stacked discs, the thickness ofsaid washers being approximately the same as the thickness of saiddiscs, each'washer having a coaxial bore therethrough,

the-bore diameter of each washer being approximately one and a halftimes that of the diameter of a propelling bullet fired axially intosaid tube bore, said discs and washers havinga thickness substantiallyless' than the length of saidpropelling bullet, said discs upon-receiving an impact from said bullet transmitting the propelling force of saidbullet tosaid tube thereby propelling said' References Cited in thevfile ofthis patent UNITED STATES PATENTS 826,293 Unge July 17, 19061,900,790 Brandt Mar. 7, 1933 2,713,262 Webster July 19, 1955'

